A NEW METHOD FOR PRESSURE SENSOR EQUILLIBRATION AND CONDITIONING

PAPAIOANNOU, G.; PROTOPAPPAS, V.C.; TSOPELAS, P.; MITROGIANNIS, C.; NIANIOS, G.; TASHMAN, S. A New Method for Pressure Sensor Equillibration and Conditioning. Brazilian Journal of Biomotricity, v. 2, n. 3, p. 176-195, 2008. Assessing pressure and contact stress distributions between two adjacent surfaces is a well established research area in biomechanics. Typical applications of measuring the interface pressure include human-machine interfaces in ergonomics, joint congruency studies in orthopaedics, in-vitro cadaveric experimentation and the design of Orthotic-Prosthetic devices. Tekscan pressure sensors are widely used in both in-vivo and in-vitro experiments. An all-round efficient equilibration and calibration approach of the Tekscan sensor system is yet to be clearly defined in the literature and is attempted here for one type of Tekscan sensors. The response of individual sensels from two 5315 Tekscan sensors for quasi-static, repeated constant and dynamic loading was investigated with the use of two methods, namely the “Bladder Method” and the “Pin Method”. In the first method, uniform pressure was applied by a bladder-equilibrator, whereas in the second loads were applied in a sensel-by-sensel approach by means of a pin attached to a frame installed on a material testing machine. The “Pin Method”, although far more laborious, is a better method for equilibration and calibration of sensors, particularly when saturation is prevalent. The pin-method also provides a better characterization of the sensor drift. It was shown that when test conditions resulted in some of the sensels being saturating due to high pressure, the loss of load data from the sensor mat could be estimated using the individual sensel output.